diff --git a/addons/claim_from_delivery/stock_picking.py b/addons/claim_from_delivery/stock_picking.py
index 3a3404bfa93..6929809bfe2 100644
--- a/addons/claim_from_delivery/stock_picking.py
+++ b/addons/claim_from_delivery/stock_picking.py
@@ -4,7 +4,7 @@ from openerp.osv import fields, osv
 class stock_picking(osv.osv):
     _inherit = 'stock.picking'
 
-    def _claim_count(self, cr, uid, ids, field_name, arg, context=None):
+    def _claim_count_out(self, cr, uid, ids, field_name, arg, context=None):
         Claim = self.pool['crm.claim']
         return {
             id: Claim.search_count(cr, uid, [('ref', '=',('stock.picking.out,' + str(ids[0])))], context=context)
@@ -12,15 +12,19 @@ class stock_picking(osv.osv):
         }
 
     _columns = {
-        'claim_count_out': fields.function(_claim_count, string='Claims', type='integer'),    
+        'claim_count_out': fields.function(_claim_count_out, string='Claims', type='integer'),    
     }
 
+# Because of the way inheritance works in the ORM (bug), and the way stock.picking.out
+# is defined (inherit from stock.picking, dispatch read to stock.picking), it is necessary
+# to add the field claim_count_out to this class, even though the _claim_count_out method
+# in stock_picking_out will not be called (but its existence will be checked).
 class stock_picking_out(osv.osv):
     _inherit = 'stock.picking.out'
 
-    def _claim_count(self, cr, uid, ids, field_name, arg, context=None):
-        pass
+    def _claim_count_out(self, cr, uid, ids, field_name, arg, context=None):
+        return super(stock_picking_out, self)._claim_count_out(cr, uid, ids, field_name, arg, context=context)
 
     _columns = {
-        'claim_count_out': fields.function(_claim_count, string='Claims', type='integer'),    
+        'claim_count_out': fields.function(_claim_count_out, string='Claims', type='integer'),    
     }